1. Field of the Invention
The present invention relates to an image display apparatus and an image display method, and, more particularly, to a technique for displaying a moved image.
2. Description of the Related Art
In recent years, there have been increased opportunities for displaying data for third parties using a large screen display in a meeting or presentation. For example, various types of data such as textual data, table data, and graphical data, which are created using application software for a personal computer, are displayed for third parties using a large screen display such as a front projector or a rear projector. In such a case, a multi-screen display function of displaying a plurality of images, which are sent from different personal computers or from a personal computer and a video apparatus, at the same time can be effectively used.
The multi-screen display function is used in television sets. As illustrated in FIG. 11, using the multi-screen display function, a first screen 110 of full screen size and a second screen 120 of reduced size which is reduced so that the second screen 120 fits within a predetermined area can be displayed. However, in the case of a general multi-screen display function, as illustrated in FIG. 11, since the second screen 120 is displayed in front of the first screen 110, a portion of the first screen 110 under the display area of the second screen 120 is hidden and invisible.
In order to improve a visual effect by arranging important image portions of a plurality of displayed screens, it is desirable that the display areas of the first screen 110 and the second screen 120 be freely movable. For example, Japanese Patent Laid-Open No. 6-30335 discloses a display method of moving a first screen so as not to overlap with a second screen.
In the method disclosed in Japanese Patent Laid-Open No. 6-30335, a time of Lm is added to a data writing time at which data is written into a memory so as to determine a data reading time at which the data is read out from the memory as illustrated in FIG. 12, so that a displayed image is shifted to the left as illustrated in FIG. 13. On the other hand, by subtracting the time of Lm from the data writing time so as to determine the data reading time, the displayed image can be shifted to the right as illustrated in FIG. 14.
However, since the image displayed after a display position has been moved extends off a screen area, a part of the image becomes invisible. Accordingly, it is difficult to see the entire area of the image. In order to see the entire area of the image, a method of compressing the image so as to fit the entire area of the image within a limited display area that has been changed in accordance with the movement of the display position can be considered. However, in this case, the aspect ratio of the image is changed, or a part of the image the detailed view of which is required is also reduced in size. This makes it difficult to see displayed information.